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A glass block, or glass brick, is both functional and decorative. Used to make walls and windows, it allows in light from another room or from outdoors. When the glass is textured, it affords privacy as well, which makes glass block ideal for shower walls and bathroom windows. You can install a glass block wall or window yourself using glass mortar and spacers.

Steps

1

Choose the right glass block for your project. Blocks with large faces will let in more light, and thin blocks are better for windows. You can use different sizes, colors and textures to create the look you want.

2

Draw a diagram of the installation.

Plan your project to use whole blocks. Glass blocks can't be cut.

Allow a space of ¼ to ⅜ inch (0.6 to 1 cm) between blocks and between the blocks and the wall, jamb or window frame. You must include the spaces for your drawing to be accurate.

You may discover that no arrangement of glass blocks will completely fill the area of the installation. Plan to add finished wood or other material to the arrangement.

3

Mix the glass mortar according to the directions. The amount of mortar you will need depends not only on the size of the project, but on the size of the blocks. Mix the mortar in batches that can be used in about an hour so the mortar won't start to set before you get a chance to use it.

4

Put down a bed of mortar and place the first row of blocks.

Place the first block. Then, trowel enough mortar onto one side of the next block so that when you set it beside the first block, the mortar fills the space between and sticks the blocks together. Add mortar to only one side of each subsequent block in the row.

The spaces between the end blocks and the wall, jamb or window frame will be filled with an expansion strip, not mortar. The expansion strip will allow the blocks to expand and contract with changes in temperature.

5

Place the appropriate spacers between the blocks. Tap the blocks snugly against the spacers with a rubber mallet. Spacers ensure that the spaces between blocks are uniform and that the weight of the upper rows don't force mortar to squeeze out of the lower rows.

Use "T" spacers around the perimeter. Press the first spacers into the mortar as the first row of blocks is installed. For the sides, screw or nail "T" spacers to the adjoining wall or window frame.

Place "X" spacers between blocks. They will ensure even spacing between blocks on the same row and between rows.

Put the spacers between blocks halfway between the back and front so they don't interfere with tooling the joints later. Leave them in place and mortar over them.

Community Q&A

Glass block mortar is a specially formulated product that is designed for glass block applications requiring white mortar joints. It can be used in both interior and exterior applications. Glass block mortar can also be used in laying brick, block, and tile where white mortar is desired. The formulation is a mixture of white cement, white sand, hydrated lime, and other waterproofing additives.

They are typically 1/4'' as the real size of the blocks is 1/4'' short of the actual measurements. (For example, an 8x8x3 block measures 7 3/4" to allow for the mortar joint.) If you are talking about head joints, I've seen them in excess of 2'', but that would mean the wrong size was built for the opening as glass block panels can be built to any size within 2''.

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wikiHow is a “wiki,” similar to Wikipedia, which means that many of our articles are co-written by multiple authors. To create this article, 9 people, some anonymous, worked to edit and improve it over time. This article has also been viewed 187,141 times.